Variable speed drive transmission



May 3, 1966 H. SCHOTTLER VARIABLE SPEED DRIVE TRANSMISSION 5Sheets-Sheet 1 Original Filed Sept. 25, 1955 ww Q Q in INVENTOR.lffzvfir ,JcA o 77 452 BY 9 6. O W

May 3, 1966 H. SCHOTTLER VARIABLE SPEED DRIVE TRANSMISSION OriginalFiled Sept. 25. 1955 5 Sheets-Sheet 2 INVENTOR. /wev Savory-45R May 3,1966 H. SCHOTTLER VARIABLE SPEED DRIVE TRANSMISSION 5 Sheets-Sheet 3Original Filed Sept. 25, 1955 INVENTOR. Ner icy/0774a? BY Q2; 6: 022%May 3, 1966 H. SCHOTTLER VARIABLE SPEED DRIVE TRANSMISSION 5Sheets-Sheet 4 Original Filed Sept. 23, 1955 JNVENTOR. oM/IPY{IE-#072251? BY 9 a OKWAM( May 3, 1966 H. SC HOTTLER VARIABLE SPEEDDRIVE TRANSMISSION n a 1 v m aw M w v S I 4 win M5 4 W Wfl m //QHIHUI\ P6 s 1 .y H M K s E w N QWHP Original Filed Sept. 23, 1955 United StatesPatent Office 3,248,950 Patented May 3, 1966 3,248,960 VARIABLE SPEEDDRIVE TRANSMISSION Henry Schottler, North Riverside, lll., assignor, bymesne assignments, to Roller Gear Ltd., Zug, Switzerland, a corporationof Switzerland Continuation of application Ser. No. 536,231, Sept. 23,1955. This application Nov. 13, 1959, Ser. No. 852,902 28 Claims. (Cl.74200) This application is a continuation of my prior co-pendingapplication Serial No. 536,231, filed September 23, 1955, now abandoned,entitled Variable Speed Drive Transmission.

The invention relates to mechanical variable speed transmissions inwhich balls rolling between inner and and outer races are used as powertransmitting means.

The essential requirements for an economical transmission of this typefor a wide speed range may be defined as follows:

(1) Balance of the heavy contact forces within the transmission so as toprevent thrusts on the shaft bearmgs.

(2) Minimum pressures at the points of contact of the power transmittingmembers for the entire speed range to prevent slippage and reduce thelosses due to friction or rolling resistance.

(3) Different contact paths of the power transmitting members atdifferent speed ratios to increase the useful life of said members.

(4) Simple mechanism for changing the speed ratio.

()Iorque responsive means which provide the necessary pressures at thepoints of contact to prevent slippage for any power to be transmitted inboth directions through zero, including shock load.

(6) Extended speed range reacting preferably from zero to a multiple ofthe input speed in both directions.

(7) Simple design for low cost production.

It appears that none of the known speed transmissions combines all thedesirable features recited above.

Some transmissions have balanced forces and attain a high efficiency ata certain speed ratio, but at other speed ratios their efiiciency curveis declining. Other devices provide a more constant efiiciency curve butonly for very limited speed ranges. Even the most recent developments,described, for instance, in the paper by Charles E. Kraus, NewApproaches to Variable Speed Drives, published in Machine Design,December 1953, succeed only in balancing the contact forces but do notsolve at the same time the other problems. In said transmissions, thepressures at the points of contact vary with the location of the contactpoints and are determined by spring pressure; too low spring pressureswill cause stoppage at certain torques, and too high spring pressureswill produce at lower torque rates higher pressures than necessary.These and other shortcomings of the known transmissions limit the speedrange from a 4:1 reduction to about a 2 to 1 speed up.

It is an object of the invention to provide an improved variable speedtransmission of the character described which can be economicallymanufactured, satisfies all the requirements set forth above and isoperative at a speed range from 00:1 (output speed Zero) to about 2 /2to 1 speed up.

Other objects and advantages will be apparent from a consideration ofthe specification and claims.

The invention will be more fully explained with reference to theaccompanying drawings in which several embodiments are illustrated, byWay of example, and in which FIG. 1 shows a first gear according to myinvention, partly in longitudinal section, and partly in side elevation;

FIG. 2 is a vertical sectional view taken on line 22 of FIG. 1;

FIG. 3 is a vertical sectional view taken on line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 1 of another embodiment of simpleconstruction according to the invention;

FIG. 5 shows still another embodiment of the invention partly inlongitudinal section, and partly in side elevation;

FIG. 6 shows a part of the transmission of FIG. 5 with balls and racesin a different position (low output speed) including a diagrammaticsketch of a hydraulic control system;

FIG. 7 is a vertical sectional View of the balls, races and ball carriertaken on line 7-7 of FIG. 6;

FIG. 8 is a vertical sectional view of the planetary gears taken on line44 of FIG. 5.

FIG. 9 is an illustration of one ball and one roller of the retainerviewed in direction E of FIG. 7;

FIG. 10 is a section of the control valve in a position for increasingoutput speed, and

FIG. 11 shows diagrammatically a hydraulic control system locatedoutside the unit.

In the embodiment of the invention illustrated in FIGS. 1 to 3, thedriving shaft is designated by the reference numeral 5 and the coaxialdriven shaft by the numeral 6. Shaft 6 is supported in the gear housing1 by a ball bearing 4. An intermediate shaft 7 is freely rotatable inthe hollow shaft 6 and at its other end freely supported in ballbearings 8 and 9 arranged inside the shaft 5.

The inner races 14 and 15 are mounted on said inter mediate shaft 7; theone inner race, 14, is fixedly secured thereto, the other inner race 15is mounted non-rotatably but for free movement in axial direction. Oneouter race 11 is mounted on shaft 5 non-rotatably but slidably in axialdirection and connected in the same way at its outer circumference withan oil cylinder 12, which forms part of a hydraulic control to bedescribed hereinbelow. The other outer race 13 is fixedly secured tosaid oil cylinder 12.

A suitable number of uniformly spaced steel transmission balls 23 arelocated in the annular groove formed by the inner and outer races.

In the shown construction, three of such balls are provided betweenrollers 24 which are freely rotatable around axes parallel to the axisof the transmission and the spinning axis of the balls 23. Said axes arecarried by a spider or carrier 25 and form preferably the stationaryinner race of a roller bearing, the outer rotatable race of which formsthe roller surface supporting the balls 23.

The carrier 25 is by means of a disc 26 rigidly connected to a bushing27, which is rotatable on ball bearings 28 and 29. Said ball bearing 29is supported by a member 33, which is centered between the gear housing1 and the cover 2. The hub 27 of the bushing 27 carries also three setsof planetary gears 35, 36 which are supported in ball bearings 37. Thesmaller planetary gears 35 mesh with an internal gear 34 secured to thehousing 1, the larger gears 36 with an external gear 32. Said gear 32 iscarried by a clutch disc 30, which is frictionally connected by ahelical spring 31 with the cylinder 12.

A spring 50 forces the inner races 14, 15 against the balls 23 and saidballs against the outer races 11, 13 with sufficient power to keep alltransmission members at all times in frictional engagement.

As will be noted on viewing the drawing, the raceways of the outer raceshave a curvature formed by a radius which is considerably greater thanthe radius of the curvature of the inner raceways. This is an importantfeature of my novel transmission and ensures an easy adjustment of thepower transmitting members over a wide speed range. I have found thatfor a smooth and efiicient operation of my transmission, the radii ofthe generating curves of the raceways and the radius of the balls shouldsatisfy the relation wherein r is the radius of the balls, r the radiusof the generatrix of the curvature of the outer raceways, and r theradius of the generatrix of the curvature of the inner raceways. From amanufacturing point of view, it may be an advantage to make r of theequation infinite, which means that the contacting surface of the outerrace assumes the form of an internal cone.

Torque responsive loading means have to be arranged between the innerraces and the driven shaft. Various constructions of such torque loadingmeans are known but I have developed an improved design of such torqueloading means or pressure changer, which design is particularly suitablein connection with my novel transmission and represented in the drawingby the reference numerals 16 to 22.

The torque responsive means shown in FIG. 1 is a friction screw devicecomprising an inner member '16 secured to the intermediate shaft 7 andan outer screw member 17 secured to a tubular extension 6 of the outputshaft 6; both members are threaded to form a helical groove for aplurality of steel balls 18 freely rolling therein. A disc 21 is pressedagainst the inner race 15 by spring 50 and retains a plurality of balls22 freely rolling between the plane faces of said inner race 15 andouter screw member 17. At the outer end of the screw device, a disc 19is secured to shaft 7 and forms an annular groove for balls 20 freelyrolling in frictional contact with said disc 19 and said outer screwmember 17.

The transmission may be adjusted by hand, but in larger units theadjustment is preferably made hydraulically, and a suitable hydrauliccontrol of the outer races is by way of example, shown in FIGS. 1-3.

The hydraulic control comprises the already mentioned oil cylinder 12fixedly connected with the outer race 13 and a disc 10 integral with ahollow shaft 10'. Disc 10 is axially slidable like a piston in cylinder12. The part 12' of cylinder 12 forms the closure of oil cylinder 46 andis slidable with a tight fit on said hollow shaft 10'. A freelyrotatable bushing 38 is slidable in axial direction between shafts andand forms part of -a slide valve operated by the member 39, which isrotatable on bushing 38 and connected with control means like 54, 55 asshown in FIG. 4. The oil for the cylinder 46 is supplied through thechannels 42, 43 of the slide valve and openings 45, by a gear pump 40,41 arranged on shaft 5. A spring loaded overflow valve 44 is providedinside a bore of shaft 5.

The above mentioned spring 31, which acts against the cylinder 12,forces thereby the outer races 11 and 13 apart against the oil pressurein cylinder 46.

. The operation of the novel drive is as follows:

Power is applied with constant input speed to the input shaft 5. Theouter races 11, 13 rotate with input speed. The planetary gears 35, 36engaged with gears 32 and 34 rotate the carrier 25 with reduced speed inthe same direction.

The balls 23 are spinning around their own axis parallel to the mainaxis of the drive and according to the rotation of the carrier 25, inplanetary fashion around the drive axis.

Due to the pressure caused by the pressure device 16, 17, 18 inproportion to the output torque, and an additional pressure by spring50, the balls 23 frictionally engage the outer races 11, '13 and theinner races '14, and force the inner races to rotate in oppositedirect-ion.

Depending on the acting diameters of the rolling members and the speedof carrier 25, a certain output speed is obtained. Said speed can bevaried by moving the outer races 11, 13 apart or together.

In the position shown in FIG. 1, the output speed will be about 1.6times the input speed. By moving the outer races 11, '13 apart into theposition indicated by dotted lines, the output speed will be about 0.07times the input speed, but in opposite direction.

This means that a torque converter with a speed range as mentioned abovewhen used as a car transmission would provide (a) a forward drive up to60% overdrive or m.p.h.

(considering S0 m.p.h. for a speed ratio 1: 1)

(b) a reverse drive up to 7% or 3.5 m.p.h., and

(c) a start to either direction from zero without clutch.

This ideal speed range is attained at a constant most economical motorspeed without disengaging the drive mechanism. Thus, full automaticcontrol governed by motor speed and torque or in connection with the gaspedal is readily obtained.

The action of the pressure chamber is as follows:

A torque applied at the output shaft will rotate the female part 17 andcause an axial displacement of part '17 to part 16 in one or the otherdirection, depending on the direction of torque or the kind of thread-RHor LH. The thus produced axial forces will be always in proportion tothe output torque and will force both inner races 14, 15 against theballs 23. The balls 20 and 22 are necessary to prevent any lockingaction between part 17 and parts 19 or 15.

The new transmission is working like a positive gear without slippage,even if shock load is applied. With output speeds around zero excessivetorque might damage the unit. Instead of a special safety clutch, thesimple springloaded disc 30 is arranged to slip when the permissibleoutput is exceeded, thus protecting internal parts of the unit.

The hydraulically operated speed change of the transmission iscontrolled by the bushing 38. If said bushing is moved to the left, oilwill be pressed through openings 45 into the oil cylinder 46. The outerraces 11, 13 are pressed together, forcing the inner races 14, -15 byballs 23 apart until the control edges 47 of the moving part 10' and thecontrol edges 48 of the set bushing 38 coincide again.

By moving the bushing 38 to the right, oil is pressed out of the oilcylinder 46 by the pressure device 16, 17, 18, the spring 50 and thespring 31 through openings 45 and chamber 49 into the oil reservoiruntil the control edges 47 of the moving part 10 and the control edges48 of the set bushing 38 are coinciding again.

Thus, every position of the control bushing 38 means a certain speedratio. Since this bushing 38 is without any load, the speed of this newdrive can be controlled with a small dial knob. The previously mentionedfull automatic control can be achieved at least partially throughsuitable automatic control of the position of the bushing 38, asschematically illustrated in FIGURE 1.

A somewhat simpler construction of the transmission which is basicallysimilar to the embodiment of the invention shown in FIGS. 1-3, isrepresented in 'FIG. 4.

In the embodiment shown in FIGS. 1-3, the ball retainer 24, 25 isrotatably mounted, which is of advantage for variable speed drivessubjected to considerable loads at zero point. Under these conditions,contact between the halls and the races at points located in thespinning axis AA ('FIG. 9) of the balls should be avoided because itwould not produce transmission of power and because it is forconstructional reasons difiicult to supply said points with oil and toprotect them against excessive wear.

However, where the requirements for a transmission are less severe, thesimplified construction of FIG. 4, which covers a speed range from zeroto about 2.5 times the input speed, is fully satisfactory. In thismodification of the transmission, the ball carrier is not rotating butmay be rigidly or frictionally attached to the housing, so that theparts 27-37 of the construction of FIGS. 1-3 can be omitted. As shown inFIG. 4, a ball carrier 51 is pressed against a disc 52 by a spring 53.When the permissible output torque is exceeded, the carrier 51 will slipon disc 52, preventing overload of the internal parts of the drive.

The control bushing 38 (FIG. I; not shown in FIG. 4) is connected with aguide member 56 slid'ably arranged on rod 57; said guide part isadjustable by a dial knob 54 over a spindle 55.

The outer races 11 and '13 are straight internal cones.

Another embodiment of the invention is illustrated in FIGS. 5 to 11.

This transmission will cover a speed range from about reverse 0.21 timesthe input speed through zero to about 1.5 times the input speed forward.Different speed ranges can be obtained by changing the proportions ofthe planetary gears. Such transmission without additional planetarygears would cover a speed range from zero to about 2.35 times the inputspeed.

The gear type according to FIG. 5 is basically the same as shown inFIGS. 1 to 4. Therefore, similar parts have been designated by the samereference numerals.

A hydraulic control for speed change is provided which allows positivecontrol in both directions by forcing the outer races together for aspeed increase and by forcing them apart for a speed decrease.

The outer race 13 is firmly secured to the cylinder 12, while the outerrace 11 is non-rotatable but axially displaceable inside cylinder 12 inclose contact thereto. Inside cylinder 12 a disc 62 is mountednon-rotatably but slidably in axial direction on shaft 5 and firmlyconnected at its outer circumference with the outer race 11. Anotherdisc 63 has a hub rigidly secured to said disc 62 and slides with itsouter periphery in close fit (with sealing ring) along an extended openend of the cylinder 12. A conicaly shaped disc 64 integral with cylinder12 slides with close fit on said hub of disc 63 and divides saidcylinder 12 into two oil chambers 71 and 72.

A slide valve 67 is located inside an opening formed in the hubs of thediscs 62 and 63. Said slide valve 67 controls the oil supply from a ringspace 70 to the oil chambers 71 and 72 by means of pairs of controledges 47 and 48.

The slide valve body may be a bushing arranged inside the hubs of thediscs 62 and 63 (FIG. or it may also be located outside the rotatingparts of the transmission or even outside the unit proper. An examplefor the last mentioned arrangement is shown in FIG. 11, where an axiallymovable rod 67' is located inside a bushing 99 connected with one of thediscs 62 or 63 (FIG. 11) preferably in such a manner that the axialdisplacement of said bushing 99 is a multiple of the correspondingdisplacement of said discs, which results in a more sensitive speedcontrol.

As noted above, the inner races 14 of FIG. 1 and 65 of FIG. 5 are fixedin axial position. The advantage of such a construction will becomeapparent on consideration of FIG. 9. On changing speed, the inner race66 (or 15, respectively) performs the entire necessary axial movement.Since the center line of the balls and both inner and outer races,indicated with line 77 in FIG. 6, is moving axially one half of thisamount, indicated by D in FIG. 9, the balls which are pressed againstthe axially fixed rollers 60, due to the torque applied, will be forcedto tilt around an axis going through their center point C, which axiscoincides with line 77 and is perpendicular to the main spinning axisA-A.

At each speed change, the balls 23 will therefore roll upon differenttracks, and the entire ball surface will be utilized more economicallywith respect to transmission Wear.

The operation of the drive illustrated in FIGS. 5 to 11 is as follows:

Power is applied with constant input speed to the input shaft 5. Theouter races 11, 13 rotate with input speed. The oil pump 82 which iskeyed to shaft 5 is ,5 pressing oil into a ring space 70, keeping theouter races in an axially fixed position. This position is predeterminedby a certain position of the valve 67 according to the desired speedratio.

The balls 23 are pressed against, and rotated, by the outer races 11,13, revolving around their fixed axis, parallel to the main axis of thedrive.

The rotating balls 23 are forcing the inner races 65, 66, which arepressed against the balls 23, to rotate in opposite direction to theouter races. The hollow shaft 98 and the inner member 16 of the pressuredevice are rotating with the same sped as the inner races 65, 66. Thebushing like part 89 of the output shaft and the internal gear 83 of theplanetary gear, which are transmitting the output torque, are forced byballs 18 of the pressure device to rotate also with the speed of theinner races 65, 66.

Since the balls 18 are located in helical threads of the inner member 16and the outer member '17 of the pressure device, the applied outputtorque will create a necessary axial pressure according to the lead ofthe helical threads, forcing the inner races 65, 66 against the balls23, preventing slippage between balls and races under all loadconditions.

For changing speed, manually (92) or automatically, the valve 67 has tobe brought into the desired position, representing the desired outputspeed. Automatic speed changing is achieved through utilization of asuit-able automatic control, as schematically illustrated in FIG- URE 6,for moving the valve 67 into the desired position in the same manner asmanipulation of the lever 92 accomplishes manual speed changing.

Since the four control edges 47, 48 of the valve bushing 67 and the hubof part 63 have to register for balanced position, any axial move of thevalve bushing 67 will be automatically followed by the same axial moveof 63 and the attached disc 62 with outer race 11.

For example as shown in FIG. 10, the valve 67 may be moved to the rightby shifting the lever 92 into the position X. Immediately, oil from theoil pump 82 and line 96 is flowing through the free ring opening underpressure into the chamber 71, moving discs 62 and 64- axially apart andat the same time discs 63 and 64 together, pressing oil out of thechamber 72 through the free ring opening into the line 97 and back to anoil reservoir 94 (FIG. 6).

This axial movement of parts 62, 63 and 64 and the outer races 11 and 13takes place until the control edges 47 and 48 are registering again andshut off the oil supply. By this action, the outer races 11 and 13 havepressed the balls 23 more to the center of the unit, squeezing the innerraces 65, 66 axially apart, causing change of contact points between thepower transmitting balls and races and thus speed increase. Afterclosing off the ring rooms 68, 69, and 70, oil from the oil pump in line96 will be pressed through an overflow valve 93 back into the oilreservoir 94, form-ing a cycle from the reservoir 94, line 95, oil pump82, line 96, overflow valve 93, oil reservoir 94.

To reduce the output speed, the valve 67 has to be moved into theopposite position by shifting lever 92 into the position Y. O-il underpressure will flow through a free ring opening into the chamber 72,forcing discs 63 and 64 apart and at the same time forcing the discs 62and 64 together; on the other hand, oil will be drained from chamber 71through a free ring opening through line 97 back into the oil reservoir94.

The axial movements of the parts 62, 63 and 64 will stop as soon as thecontrol edges 47 and 48 register again. During this action, the outerraces 11 and 13 are forced apart, while the balls 23 are pressed againstthe outer races by components of the axial forces, actuated by thepressure device, which is forcing the inner races 65 and 66 together,always in proportion to the output torque.

At low output speeds, when due to a small contact angle the forcestransmitted by the pressure changer 7 might be insufficient for a safecontact against the apart moving outer races, additional forces F,resulting from the reaction forces against the rollers 60, due to thetransmitted torque T at each ball 23 will press the balls 23 outward(see FIG. 7).

Variable speed drives according to the present invention, of which theinner races are driven with constant speed will allow a speed range ofthe outer races from approximately 0.4 to about times the input speed,depending on the kind of application.

The same unit with outer races driven with constant speed would allow aspeed range of the inner races from zero to about 3 times the inputspeed, if the ball retainer is not rotating.

Since a speed reduction down to zero or even through zero into reverseis desirable in most applications, the transmission, of which the outerraces are driven with constant speed, will be preferable.

I claim:

1. A variable speed drive transmission comprising a driving shaft, adriven shaft coaxial with said driving shaft, a pair of inner races, apair of outer races, one of said pairs of races being operativelycoupled to said driving shaft, the other pair of said races beingoperatively coupled to said driven shaft, said races forming an annulargroove, a plurality of balls in fixed circumferential spacedrelationship radially displ'aceably supported in said groove for freerolling movement in contact with said pairs of races, the races of saidouter pair being symmetrically shiftable with respect to the medianplane of said balls, at least one race of said inner pair being axiallydisplaceable, rollers arranged circumferentially between, and in contactwith, said balls, and mounted for free rotation on axes parallel to saidshafts, and a spider carrying said rollers, said outer races having acontact surface formed by a generatrix of greater radius than thegeneratrix of the contact surface of said inner races, and meansincluding a reaction element drivingly connected with said outer racesand said spider, for controlling their relative rotation.

2. A variable speed drive transmission as defined in claim 1, whereinthe radii of said generatrices satisfy the relation wherein r is theradius of the balls, r the radius of the generatrix for the contactingsurface of the outer races, and r; the radius of the curvature of theinner races.

3. A variable speed drive transmission as claimed in claim 2, whereinthe outer races are straight internal cones, r being infinite.

4. A variable speed drive transmission comprising a driving shaft, adriven shaft coaxial with said driving shaft, a pair of outer racesoperatively coupled and rotating with said driving shaft, a pair ofinner races operatively connected with said driven shaft, one of saidinner races being axially displaceable and the other race heldstationary in axial direction, said inner and outer races forming anannular groove, a plurality of balls supported in said groove for freerolling displaceably in contact with said pairs of races, the races ofsaid outer pair being symmetrically shifta'ble with respect to themedian plane of said balls, rollers arranged circumferentially betweenand in contact with said balls, and mounted for free rotation on axesparallel to said shafts, and a spider carrying said rollers, thecontacting faces of said races and balls satisfying the relation whereinr is the radius of said balls, r the radius of the curvature of theouter races, and r, the radius of the curvature of the inner races, andmeans including a reaction element drivingly connected with said outerraces and said spider for controlling their relative rotation.

5. The variable speed drive transmission as defined in claim 4, whereinthe outer races are straight internal cones, r being infinite.

6. The variable speed drive transmission as defined in claim 4 includingspring means forcing said inner races against said balls.

7. The variable speed drive transmission as defined in claim 4 includinghydraulic means controlling the axial displacement of said outer races.

8. The variable speed drive transmission as defined in claim 7, whereinsaid hydraulic control means include a cylinder and piston rigidlyattached to one of said outer races.

9. The variable speed drive transmission as defined in claim 7,comprising an oil cylinder rigidly attached to one of said outer races,said cylinder having a hub freely movably mounted on said driving shaft,a ring opening in said hub, and a bushing-like valve arranged adjacentsaid opening for controlling the oil supply to said cylinder.

10. In a variable speed drive transmission according to claim 6comprising an intermediate shaft coaxially arranged between driving anddriven shaft, and a torque responsive coupling means formed by anantifriction screw, with an inner member secured to the intermediateshaft and an outer member secured to the driven shaft.

11. In a variable speed drive transmission including a drive shaft and adriven shaft, change speed mechanism drivingly interconnecting saidshafts comprising a pair of inner races operatively coupled to one ofsaid shafts, a pair of outer races operatively coupled to the other ofsaid shafts, said inner and outer races having respective surfacesdefining an annular groove therebetween, said surfaces of said outerraces being formed by a generatrix of greater radius than a generatrixforming said surfaces of said inner races, a plurality of transmissionballs disposed in said groove for rolling movement in contact with saidsurfaces of said pair of races, reaction means operatively associatedwith said transmission balls, and means for shifting at least one ofsaid races to change the positions of contact between the balls and saidsurfaces of said races to thereby change the drive ratio between saidshafts.

12. A variable speed drive transmission as defined in claim 11 whereinthe radii of said generatrices satisfy the relation wherein r is theradius of the balls, r is the radius of the generatrix of said surfacesof the outer races, and r is the radius of the generatrix of saidsurfaces of the inner races.

13. In a variable speed drive transmission including a drive shaft and adriven shaft with change speed mechanism drivingly interconnecting saidshafts including a pair of inner races and a pair of outer races withtransmission balls in engagement with respect to the surfaces of theraces in an annular groove therebetween, the improvement comprisingradii of the generatrices of said surfaces of the races satisfying therelation wherein r is the radius of the balls, r is the radius of thegeneratrix of said surfaces of the outer races, and r; is the radius ofthe generatrix of said surfaces of the inner races.

14. In a variable speed drive transmission including a drive shaft and adriven shaft, change speed mechanism drivingly interconnecting saidshafts comprising a pair of inner races operatively coupled to one ofsaid shafts and rotatable with said one shaft, a pair of outer racesoperatively coupled with the other of said shafts and rotatable withsaid other shaft, said inner and outer races having respective racewaysdefining an annular groove therebetween, said raceways of said outerraces being formed by a generatrix of greater radius than a generatrixforming said raceways of said inner races, a

- 9 plurality of transmission balls disposed in said groove for rollingmovement in contact with said raceways, means including a reactionelement and a control element operatively associated with saidtransmission balls for controlling rotation of said races relative tosaid transmission balls, means for relatively shifting said races whilemaintaining the respective pairs of races symmetrical with respect tothe median plane of said balls to change the positions of contactbetween the balls and said raceways to thereby change the drive ratiobetween said shafts, and means responsive to torque of said driven shaftfor increasing the contact pressure between said balls and said raceswith increasing driven shaft torque.

15. A variable speed drive transmission as defined in claim 14 whereinthe radii of said generatrices satisfy the relation wherein r is theradius of the balls, r is the radius of the generatrix of said r-acewaysof the outer races, and r is the radius of the generatrix of saidraceways of the inner races.

16. In a high speed variable ratio transmission: a power input shaft; 2.power output shaft; inner race means on one of said shafts comprisinginner race rings and means for urging them toward each other; outer racemeans supported in a position around said inner race means, comprisingouter race rings supported so as to be movable relatively toward eachother; balls disposed between said inner and outer race means in rollingengagement with said race rings thereof; means for controlling thepositions of said balls; and means for urging said outer race ringstoward each other, comprising walls forming a fluid receiving chamber,one of said walls being movable by the pressure of said fluid, meansconnecting said movable wall to said outer race means so as to move thelast named rings thereof toward each other, means for delivering fluidunder pressure to said chamber from a source of fluid under pressure,and means for limiting the pressure of said fluid in said chamber.

17. In a high speed variable ratio transmission: a power input shaft; apower output shaft; inner race means on one of said shafts comprisinginner race rings and means for urging them toward each other; outer racemeans supported in a position around said inner race means, comprisingouter race rings supported so as to be movable relatively toward eachother; bal-ls disposed between said inner and outer race means inrolling engagement with said race rings thereof; means for controllingthe positions of said balls; and means for urging said outer race ringstoward each other, comprising walls forming a fluid receiving chamber,one of said walls being movable by the pressure of said fluid, meansconnecting said movable wall to said outer race means so as to move thelast named rings thereof toward each other, means for delivering fluidunder pressure to said chamber from a source of fluid under pressure, acontrol valve for con trolling the flow of fluid into said chamber, andpressure regulating valve means for limiting the pressure of said fluidin said chamber.

18. In a high speed variable ratio transmission: a power input shaft; apower output shaft; inner race means on one of said shafts comprisinginner race rings and means for urging them toward each other; outer racemeans supported in a position around said inner race means, comprisingouter race rings supported so as to be movable relatively toward eachother; balls disposed between said inner and outer race means in rollingengagement with said race rings thereof; means for controlling thepositions of said balls; and means for urging said outer race n'ngstoward each other, comprising an annular cylinder surrounding the otherof said shafts, an annular piston in said cylinder, means connectingsaid piston to said outer race means so as to move said outer race ringstoward each other in response to movement of said piston by fluidpressure in said cylinder, a delivery duct for the delivery of fluidunder pressure into said cylinder, control valve means for controllingthe flow of fluid through said duct to said cylinder, and auxiliaryvalve means connected to said cylinder so as to be responsive to fluidpressure therein, for limiting the magnitude of the fluid pressure whichmay be built up in said cylinder.

19. In a variable ratio transmission: a power input shaft; a poweroutput shaft; a variable ratio transmission connecting said shafts, saidtransmission having means acting in response to pressure increments tochange the ratio thereof from one extreme to the other; and means forapplying pressure increments to said pressure responsive means of saidtransmission comprising an annular cylinder around one of said shafts,an annular piston in said cylinder, means for connecting said piston tosaid means of said transmission which acts in response to pressureincrements, a duct for connecting said cylinder to a source of fluidunder pressure, valve means for controlling the flow of fluid throughsaid duct to said cylinder, and means for limiting the pressure of saidfluid in said cylinder.

20. In a variable ratio transmission: a power input shaft; a poweroutput shaft; a variable ratio transmission connecting said shafts, saidtransmission having means acting in response to pressure increments tochange the ratio thereof from one extreme to the other; and means forapplying pressure increments to said pressure responsive means of saidtransmission comprising walls forming a fluid receiving chamber, one ofthe walls of said cham her being movable in response to fluid pressuretherein, means connecting said movable wall to said pressure responsivemeans of said variable ratio transmission, a duct connecting saidchamber to a source of fluid under pressure, valve means for controllingthe flow of fluid through said duct to said chamber, and means forlimiting pressure of fluid in said chamber.

21. In a variable ratio transmission: an inner member having a pair ofinner complementary race rings thereon; an outer member around saidinner member having a pair of outer complementary race rings thereonfacing said inner race rings; balls arranged between said inner andouter race rings and in rolling engagement therewith; a third memberbetween said inner and outer race rings and having spaces for saidballs; means supporting two of said members so that they may revolvearound the axis of said inner and outer members; means supporting theremaining of said members so as to have reaction against rotation; meansfor urging the inner race rings toward each other; and an annularcylinder and piston arranged adjacent one of said outer race rings forurging said outer race rings toward each other.

22. A drive comprising an inner pair and an outer pair of axiallyseparable concentric race rings, planetary means having rolling contactwith each race ring, a torque loading device tending to close togetherone pair of said race rings, and an automatic control adjustablycontrolling the separation of the other pair of race rings as :afunction of the variations in driving speed.

23. A drive comprising an inner pair and an outer pair of axiallyseparable race rings, planetary members having trolling contact witheach race ring, a torque loading device tending to close together onepair of said race rings, the other pair of said race rings including amovable member having a motive pressure surface formed thereon,continuous biasing means preloading said race rings, means for confiningpressurized fluid behind said motive surface, and means forcommunicating fluid pressure to said motive surface to load said movablemember as a function of the speed of one of said race rings.

24. In a drive mechanism, four load-delivering race rings confining anannular row of planetary balls, two of said race rings comprising a pairof rings including an output ring and an axially movable adjustablespeed control ring, preloading means continuously biasing said racerings, and means confining a supply of fluid pressure hehind said speedcontrol ring to adjust said speed control ring axially.

25. In a drive mechanism, four load-delivering race rings confining anannular row of planetary balls, two of said race rings comprising a pairof rings including an output ring and an axially movable adjustablespeed control ring, continuous biasing means preloading said race rings,and variable loading means including a motive surface on said speedcontrol ring, means confining fluid behind said motive surface, andmeans to supply fluid pressure to said motive surface as a function ofthe speed of one of said race rings.

26. In a drive mechanism, four load-delivering race rings confining anannular row of planetary balls, two of said race rings comprising a pairof rings including an output ring and an axially movable adjustablespeed control ring, the other two of said rings comprising an input ringand an axially adjustable torque-reacting ring, each of said ringshaving a curved bearing surface closely approximating the curvature ofthe balls but being of sufficiently greater curvature to afford amaterial change of contact angle through radial movement of the balls,means for moving said speed cont-r01 ring as a function of the speed ofone of said race rings and means for adjusting said torque reacting ringas a function of load or torque reaction.

27. A speed ratio power transmission mechanism comprising a plurality ofconcentrically disposed race rings and an annular row of balls held inrolling contact with each of said race rings, said race rings includingan input ring and an output ring, each facing the same way and one beingfixed against relative axial displacement and further including ringmeans facing the opposite way, said ring means being axially movable andincluding a back face forming together with adjoining means a pressurecontrol chamber, and an automatic control supplying pressurized fluid tosaid pressure control chamber for selectively moving said ring meanstoward said annular row of rings as a function of the speed increase.

28. In a variable speed drive transmission including a drive shaft and adriven shaft, change speed mechanism drivingly interconnecting saidshafts comprising a pair of inner races coupled for rotating with one ofsaid shafts and adapted for relative axial shifting, -a pair of outerraces coupled for rotating with the other of said shafts and adapted forrelative axial shifting, said inner and outer races having respectiveraceway surfaces defining an annular groove therebetween, a plurality oftransmission balls disposed in said groove for rolling movement incontact with said surfaces of said pairs of races, reaction meansoperatively associated with said transmission balls, said racewaysurfaces of said inner and outer races being flatter than the surfacesof said transmission balls, means for shifting the races of one of saidpairs toward one another to shift said transmission balls radially andto thereby change the speed ratio between said shafts, and meansassociated with the other of said pairs of races for urging said racestoward one another with a force varying as the torque on said drivenshaft.

References Cited by the Examiner UNITED STATES PATENTS 1,526,493 2/1925Dolton 74--796 1,686,446 10/ 1928 Gilman 74796 1,691,625 11/1928 Chilton74-796 2,076,057 4/ 1937 Almen 74-208 2,874,592 2/ 1959 Oehrli 74-7962,901,924 9/1959 Banker 74-796 X 2,905,026 9/1959 Oehrli 74-l90.52,941,422 6/1960 Barish 74-796 FOREIGN PATENTS 102,992 4/ 1926 Austria.446,140 6/ 1927 Germany. 343,813 10/1936 Italy. 282,491 8/ 1952Switzerland.

DON A. WAITE, Primary Examiner.

SAMUEL SPINTMAN, BROUGHT ON G. DURHAM,

Examiners.

1. A VARIABLE SPEED DRIVE TRANSMISSION COMPRISING A DRIVING SHAFT, ADRIVEN SHAFT COAXIAL WITH SAID DRIVING SHAFT, A PAIR OF INNER RACES, APAIR OF OUTER RACES, ONE OF SAID PAIRS OF RACES BEING OPERATIVELYCOUPLED TO SAID DRIVING SHAFT, THE OTHER PAIR OF SAID RACES BEINGOPERATIVELY COUPLED TO SAID DRIVEN SHAFT, SAID RACES FORMING AN ANNULARGROOVE, A PLURALITY OF BALLS IN FIXED CIRCUMFERENTIAL SPACEDRELATIONSHIP RADIALLY DISPLACEABLY SUPPORTED IN SAID GROOVE FOR FREEROLLING MOVEMENT IN CONTACT WITH SAID PAIRS OF RACES, THE RACES OF SAIDOUTER PAIR BEING SYMMETRICALLY SHIFTABLE WITH RESPECT TO THE MEDIANPLANE OF SAID BALLS, AT LEAST ONE RACE OF SAID INNER PAIR BEING AXIALLYDISPLACEABLE, ROLLERS ARRANGED CIRCUMFERENTIALLY BETWEEN, AND IN CONTACTWITH, SAID BALLS, AND